Tag Info

Hot answers tagged

14

According to this link sound (especially high frequency sound) is more attenuated in fog, because it is dispersed by the (billions of) air-water interfaces of all the droplets. This is one reason why a fog horn is a very low sound - low frequencies travel further, especially in fog. For echolocation you want to use high frequencies, and fog is more ...


5

Internal friction in the metal of the bell eventually will bring the ringing vibrations to an end. The bell vibrates when it rings, making its molecules more energetic and creating heat. Bonding between the molecules of the bell resist the vibrations, and eventually the strength of the molecular bonds will create enough friction to bring the vibrations ...


5

The cochlea has a complex physical structure, with multiple membranes and fluid-filled chambers. Therefore to explain the separation of frequencies along the basilar membrane of the cochlea is complex to. Sure, there are a lot of very general descriptions (even the answer of theblackcat) and a lot never go into the actual physics of the system. This ...


4

Anything that "suspends" the bell - whether it be a bolt, a piece of string, or a magnetic field - is applying a force. When the bell vibrates, this vibration will be transmitted. This is because the force of a magnet is a function of position - you can only get magnetic attraction because of a divergence of the field, so if you move, the force changes and ...


2

Your error is that you assume it takes 2.00s seconds for the ping to reach the cliff and an additional 1.98s to return. Without knowing the distance to the cliff, we can't qualify that assumption. Besides that, the only thing we need for the calculation is the difference in period of the outgoing and incoming pings. With a single ping you can calculate the ...


2

The round trip time of the ping is unknown; but we do know that the difference in round trip time between sub stationary and sub moving is 0.02 seconds. Let us write $D$ for the distance to the cliff when you send the ping; if you are traveling at a speed $v$, and the speed of sound in water is $c$, then we can write down the round trip time as follows ...


2

Sound waves can be emitted not only by vibrating bodies, but whenever there are pressure differences as the result of thermodynamical instability. Therefore even putting out the cigarette can produce sound cause of high temperature (and therefore pressure) differences. It's not an event with pronounced frequency characteristics, because the differences ...


1

May I ask what you think of as sound? If sound is the vibration of air- or in general any material agent- then sound is the sensation you get from the changes in the pressure of the air, it's what reaches your ear and then produces some signals interpreted in your brain. Sound is the vibration, not something produced by the vibration. This vibration which ...


1

The most common approach to model the sound radiation from a vibrating body is generaly the same as in all wave cases: continuity is the key. Let's say that a sphere is vibrating (changing it's volume periodically), then the acoustic velocity of the air particles just on the boundary with the body must be the same as the velocity of the sphere surface. It ...


1

I know this question is technically already answered, but there were several things missing from the answers that I thought should be mentioned (I am writing a review paper comparing different regions of space so I had these numbers at hand already as well). The speed of sound in space has multiple meanings because space is not a vacuum (though the number ...


1

Perhaps I could share some idea for further research. If we could make actual and correct pressure measurements in the cochlea to reveal wether the non-stationary Bernoulli effect is a good description of the actual physics-of-how-the-cochlea-isolates-frequencies-along-its-length? I would consider: I would propose to use a pitot tube, with sensor in the ...


1

You correctly assumed that sound in space does not propagate ( the density of gas molecules is between 1 per cubic meter and 1 per cubic centimeter, too low to efficiently propagate sounds ). But the Camera is mechanically attached to the space suit, which contains various mechanical parts, like a thermal control system to manage the temperature inside the ...


1

For our three compartment hearing sense, from a physics point of view, there is a basilar membrane stimulation, from base to apex, in its pathway in the cochlea, to a place on the basilar membrane. By periodic movement of perilymph, non viscous fluid, backwards and forewards, in the cochlear duct meet the conditions of a potential flow. The basilar ...


1

Neutrinos passing through you. Photons from the sun. The tangential velocity of many points on the Earth. The speed of beta particles.


1

From the Wikipedia article on fog: Sound typically travels fastest and farthest through solids, then liquids, then gases such as our atmosphere. The distance the water molecules are from each other, and temperature, are the reasons sound is affected during a fog condition. Molecule effect: Though fog is essentially water, the molecules are barely ...


1

1/f spectra have the unique distinction of being "scale invariant" in the sense that the energy in an interval df is proportional to df. The 1/f spectra in fact have the property that the in an interval with width df available energy is proportional to df but not with f. There, namely "scale invariant" attribute for. It is not the energy, but the signal ...


1

One of the ways of motivating the multipole expansion is as follows: consider a system of charges (more generally, sources, but let's consider the electrostatic case in particular) $q_i$ with position vectors $\mathbf{r}_i$. We want to calculate the electrostatic potential (more generally, whatever field you are interested in) $\phi$ at a point $\mathbf{R}$, ...


1

Here's an article about acoustic version of laser named SASER. http://en.wikipedia.org/wiki/Sound_amplification_by_stimulated_emission_of_radiation It can emit very directed acoustic field. As far as I know, present versions have quite limited posibilities, but if you're writing SF it may be inspirational.If SASER's wave can propagate in human body, which ...


1

The reason D is the "correct" answer, is because the key word best, is used. Although any answer may not be 100% correct, if at least one of the answers is better than the others, then that would make it the correct answer. A and B are eliminated because the amplitude should decrease as one moves away from the XY center line. C is eliminated because it ...



Only top voted, non community-wiki answers of a minimum length are eligible